There are differences wrt to ISRU such as CO2+nitrogen atmosphere, perchlorate soil, ice underground vs (probably) icy regolith containing CHON elements and more difficulty with solar power on Mars, but IMO these are extremely trivial compared to the hundred thousand things that must happen internally for such a city to not collapse. Also, it appears that both have the resources necessary to create methane/oxygen propellant.

You also can and should do a lot of this on earth. However there are some things you cannot finalise on earth. For most statistics the lunar poles are a more extreme problem than Mars. For most issues if your equipment works on both earth and the moon it will work on Mars. If Luna gravity proves sufficient for health then so is Mars gravity.

Although in most statistics the moon is harder, you could get home in 4 days. You could probably survive in your suit that long. Launch windows are frequent, landing is less scarily complex.

Would it be worthwhile to try building a full-blown working colony on the Moon, before risking sending many people to Mars? Or would it be an unnecessary distraction from focus on Mars?

Perhaps with a working lunar colony, it could expose any deeper problems that might not be exposable short of a full reality test. While this is in progress, the spaceflight operations supporting such a lunar colony could still iteratively improve to bring costs down in the meantime

As far as the lunar surface, there would be testing powered landings. Significant technologies needed for Mars, ISRU and aerocapture/aerobraking namely, would be impossible to test on Luna, but, so long as it is scaled for Mars' greater gravity, the propulsive system could be flown during Lunar missions.

Habitats could be tested as well; considering Mars' atmosphere is barely one percent Earth's what difference there is between Mars and Luna relate to the larger temperature variations on Luna. An inflatable habitat, for example, could handle both so long as it could handle the hot and cold spikes during a Lunar month; i.e. a short term test of a hab on the Moon would prove it could be stable on Mars.

There could be arguments that it's more cost effective to test such things strictly on Earth, but another way to look at it is how NASA's constantly forced back and forth between goals due to political whims...which will be inevitable despite efforts to minimize such madness. Employing vehicles and equipment that are adaptable to both environments ensures flexibility and redundancy. A Mars vehicle might be overpowered for Lunar standards, but the Moon is always more conveniently located.

Antarctica and Northern Canada would be much less expensive (and safer) places to test a lot of this stuff, except hab reliability in very low pressure. Everything else that is specific to Mars (ISRU chemistry) either can't be done on the Moon either, or can be simulated on Earth (such as living with 40 minute communication delays). Indeed, some people have already been doing this.

Powered descent and landing does not need to be tested on the Moon first; this is well understood technology on both Earth and Mars.

Having a million people live away from Earth and running profitable industries.

Colonizing space is not just about technology. It is also about business models and humans. The moon has far more immediately available business models or colonization schemes available to it than Mars does and is easier to monetize. Experience with running a profitable business on the moon will likely translate better into running a profitable venture on Mars than any single technology would.

For a variable Isp spacecraft running at constant power and constant acceleration, the mass ratio is linear in delta-v. Δv = ve0(MR-1). Or equivalently: Δv = vef PMF. Also, this is energy-optimal for a fixed delta-v and mass ratio.

Powered descent and landing does not need to be tested on the Moon first; this is well understood technology on both Earth and Mars.

Mars landing is radically different to a Moon landing, though some technologies are common - but not enough to justify test missions to the Moon on the way to Mars. The Moon remains, however, a worthwhile near-term goal - and probably a more politically acceptable one for state space agencies.

Testing semi closed habitats in low gravity, exposed to galactic radiation. near vacuum and dangerous dust. We need to prove the reliability of these habitats before sending them 24 months away from any spare parts or other help.

Yeah I think the important thing is that you are stuck somewhere that forces a moderate fraction of your budget to go to LS, self sufficiency and ISRU. In this case being stuck may actually be a good thing. It would trap some budget into actually being applied to space settlement despite politicians actively fighting money escaping to any useful technology development.

Antarctica and Northern Canada would be much less expensive (and safer) places to test a lot of this stuff, except hab reliability in very low pressure. Everything else that is specific to Mars (ISRU chemistry) either can't be done on the Moon either, or can be simulated on Earth (such as living with 40 minute communication delays). Indeed, some people have already been doing this.

Powered descent and landing does not need to be tested on the Moon first; this is well understood technology on both Earth and Mars.

Yes the landing part is fairly irrelevant to mars. At least it is not that hard or new so not a huge diversion.. apart from a whole separate vehicle. Mars landing really is different and hard.

I think people should always understand that for any space project, 99.99% of it always has to happen on earth. Look at Apollo for example. There would only be a moderate benefit to testing on the moon so it would have to be pretty cheap. Testing in both earth and zero gravity should be enough.

The big argument for the moon is that Mars is too expensive to begin. However.. constellation. If something with twice the performance of Altair and a fraction of the budget was suddenly pulled out of a hat I would say go for it, but the politics are so corrupt you would pretty much have to develop it in stealth mode. :p

I still like the lunar poles as a target but Im not a mars-firster, or a moon-firster. The moon might not lead to mars at all. After mastering the moon we might proceed to phobos and the asteroids. I also like the idea of a DSH in high lunar orbit and a small fleet of SEP tugs delivering asteroid samples regularly. I think that would be a much better way of mastering asteroid colonisation than going to an asteroid. It is much safer and would not tie you to just one sample when asteroids are so diverse, from solid iron to 20% volatile.

What certainly can be tested on moon: How people react on long term living in a low-g environment. Currently we have virtually zero experience what even living a week unter 1/6th g means to the body. If it works at 1/6th g, it certainly works at 1/3rd g.

I expect it to be better than zero-g, but who knows, how our body will react to it, unless we try it.

What certainly can not be tested on moon: Greenhouses. 14 days daylight, puts some plants under severe stress. 14 days night, and quite a lot of plants just die.

And a running food supply is rather important...

Habitats, rovers, and so on: If it works on the moon, it certainly works on mars.

In what ways could the Moon serve as a convenient testing ground for things that might be used on Mars?What things could be tested on the Moon before trying them out on Mars?

Almost nothing, IMO. Landing is deeply different. The environment for habs (and their life support and power systems) is too different (the moon has no convection effects, enormous temp swings, and maybe double the radiation load.) Gravity and regolith are different enough to rule out common rovers, space-suits, etc.

Basically the difference between Mars and the moon is about as much as between Mars and Earth, and Mars and LEO. So you can test the majority of systems on Earth or in orbit as well as you can on the moon.

Mars, Earth, the moon, LEO are all about equidistant from each other, in terms of unique environments versus common hardware.

(If there's not too much mixing from micrometeorite bombardment, the polar ice might preserve layers corresponding to the moon's history of asteroid and comet bombardment. In order. I would expect that would be staggeringly useful to planetary scientists.)

Yeah I think the important thing is that you are stuck somewhere that forces a moderate fraction of your budget to go to LS, self sufficiency and ISRU. In this case being stuck may actually be a good thing. It would trap some budget into actually being applied to space settlement despite politicians actively fighting money escaping to any useful technology development.

However, if you are "stuck" on the moon, it would mean that the program specifically didn't deliver those things.

Just as Constellation, as VSE, was originally meant to develop ISRU fuel technology, but instead quickly devolved into an equatorial base. Then devolved further to a handful of flags'n'footprints Apollo-on-steroids landings before being cancelled entirely.

A non-cancelled Constellation, stripped of everything useful while still somehow consuming all available funding. That's what "being stuck" means.

However, if you are "stuck" on the moon, it would mean that the program specifically didn't deliver those things.

Just as Constellation, as VSE, was originally meant to develop ISRU fuel technology, but instead quickly devolved into an equatorial base. Then devolved further to a handful of flags'n'footprints Apollo-on-steroids landings before being cancelled entirely.

A non-cancelled Constellation, stripped of everything useful while still somehow consuming all available funding. That's what "being stuck" means.

IMO, which I dont know if I can really justify past an impression, is that just doing sorties was never going to happen (again ). I think that at the point the goal slipped back from a base it was already in freefall. It is like we went from 105% to 95%, and on one level that might have looked like a small change but really it was the difference between incrementally growing our presence on the moon and doing nothing, not even getting there.

Consider just having altair for example. I can't absolutely argue they could not have done a few sorties and then collapsed. But being stuck imples it is politically sustainable. I think common sense and penny pinching would at some point allow landing one Altair within driving distance of the previous and calling that a good mission. At that point you have the situation of reuse of assets on the surface, such as the rovers, power and perhaps habitable section (if any were left behind, I forget).

If you can get to the moon regularly you cannot help but have a tiny bit extra that can go into infrastructure and saving costs by doing the actually useful things. It might not seem a lot but it could actually be an infinite amount more than the situation of a starving elephant in a room full of peanuts, which results in nothing but eventually a dead elephant and in the meanwhile not even a single spare peanut.

The Moon and Mars are sufficiently different that I don't think it would be efficient to reuse much technology between the two missions. So I agree that the argument of reuse of technology is not a good one. However, what I do see as useful is the experience gained in performing complex Lunar missions. That experience is what I believe will lead to a successful Mars mission.

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Akin's Laws of Spacecraft Design #1: Engineering is done with numbers. Analysis without numbers is only an opinion.

Going to the Moon may have an additional "psychological effect" on the public by having them get accustomed to the idea that we can "live off world" on a regular basis on "another" celestial body and that is not under the realm of science fiction... Let's keep in mind that it doesn't have to always be NASA...

How similar are the regolith fines in the two environments? Both are near vacuum, but Mars perhaps has enough atmosphere that the particles will be more rounded than the Moon's notoriously sharp, interlocking granules.

Nevertheless, I think a lot of work could be done in learning how to manage dust in a nearly-Mars-like environment, with normal cyclng of seals and mechanical joints. You might counter-argue that it could be done with regolith simulant in vacuum chambers on Earth.

Paul451: why would suits be significantly different? Heat-load is the only major difference I can think of.

How similar are the regolith fines in the two environments? Both are near vacuum, but Mars perhaps has enough atmosphere that the particles will be more rounded than the Moon's notoriously sharp, interlocking granules.

Nevertheless, I think a lot of work could be done in learning how to manage dust in a nearly-Mars-like environment, with normal cyclng of seals and mechanical joints. You might counter-argue that it could be done with regolith simulant in vacuum chambers on Earth.

Paul451: why would suits be significantly different? Heat-load is the only major difference I can think of.

It's like going to Sahara in order to prepare for an expedition in Antarctica. The greatest benefit is the organizational experience of having done any kind of exploration mission. But much of the equipment and operations must be different. The Alaskan Husky and the skis are not so useful in Sahara. And the differences between the Moon and Mars are greater than differences between any regions on Earth.

Gravitation affects all kinds of structural requirements and mechanics of machinery. With less than half the gravity, the mass sent to the Moon could be smaller than the mass sent to Mars to do the same thing. I do think that if a system works both on Earth and in microgravity, then it will work also on both the Moon and Mars. But a one-design-fits-all-g will cost more than an optimization.

Temperature variations affects many aspects of construction and choice of materials as well as what activities can and must be performed when. But there are big geographic variations in temperature, so the choice of landing site might mitigate this.

The diurnal cycles make the energy supply system requirements very different. A day or a month, and a factor of two difference in insolation daytime, are important differences not only for solar electric generation and power storage and usage, but also for day and night activities for both robots and humans. Power and daily schedule are of course most fundamental for mission activities, which in turn dictate the design of many aspects of the mission. But a mission to a Lunar pole would be much more Mars like.

Travel distance put the Moon and Mars in two different categories. Apollo could fly astronauts without a toilet, for example. Radiation and microgravity are problems for a Mars mission which are not relevant for a Moon mission.

Time spent on the surface is a similar major difference. A two week Moon mission could spend all the time on the dayside or on the nightside and does not need to design for both cases. It can also abort to Earth over a weekend any day. A Mars mission on the other hand would last almost an entire Martian year with its seasonal changes. (One can make a short Mars mission, staying only a week or so on the surface, but that would drastically lower science return and increase the return travel time anyway).

Light travel time requires autonomous operations on Mars, while a Moon mission could be remotely controlled from Earth. The ISS is more of a laboratory than a spaceship, many of its systems are managed by staff on the ground, and still it is criticized for having its crew spend much more time on maintenance than science. A concept similar to the ISS could be used as a Lunar base, but in order to fly to Mars everything has to be redesigned so that the crew and onboard computers can handle everything which needs to be done within an hour or so themselves.

Dust is different. On the Moon they are very abrasive, while on Mars it blows around with the wind. Opportunity spending 10+ years on Mars demonstrates that this is not one of the biggest concerns. Nor do micrometeorites or mars-/moonquakes seem to be important considerations for early missions.

In situ resource utilization will be very different. Mars CO2 atmosphere is relatively easy to refine while on the Moon heavy mining equipment is the only option, unless polar ices can be extracted simply by heating it.

Science goals would be different. Several branches of planetary scientists are interested in one of the objects but not both. Astrobiology and atmospheric science for example.

In many ways we can simulate Mars' environment better in labs on Earth, than we could on the Moon. I'm tired of all the talk about the Moon as a "stepping stone to Mars". It would actually be much more expensive and take much more time to design equipment that can work both on the Moon and on Mars, than to just simply go to one of them and optimize for that. We should go to the Moon to stay on the Moon. And we need different kinds of mission designs for Sahara and Antarctica.

Powered descent and landing does not need to be tested on the Moon first; this is well understood technology on both Earth and Mars.

Mars landing is radically different to a Moon landing, though some technologies are common - but not enough to justify test missions to the Moon on the way to Mars. The Moon remains, however, a worthwhile near-term goal - and probably a more politically acceptable one for state space agencies.

The Moon and Mars are sufficiently different that I don't think it would be efficient to reuse much technology between the two missions. So I agree that the argument of reuse of technology is not a good one. However, what I do see as useful is the experience gained in performing complex Lunar missions. That experience is what I believe will lead to a successful Mars mission.

As far as NASA, I am in agreement.

For SpaceX, even though Luna and Mars are quite different, landing BFS on the moon would be one way to check out some functionality before heading to Mars. NASA would likely need completely different equipment for each destination. However, BFS is so robust that they might possibly be able to do some practice landings on Luna with little to no modifications. They might even be able to several takeoffs and landings with the same craft before heading back to Earth. Sort of a celestial version of touch and go.

I could even see NASA leasing a BFS and purchasing BFR services for a lunar science program while SpaceX focuses on Mars.

A reusable lunar crew lander capable of traveling round trip between the Earth-Moon Lagrange points and the Lunar surface on just on fueling would also be capable of landing and taking off from Mars-- if it utilized an ADEPT or HIAD deceleration shield.

The delta-v for landing on Mars after the deceleration shield is discarded would be less than 550 meter per second. So most of the vehicle's propellant could be used for taking off from the Martian surface to low Mars orbit.

About the only commonality would be equipment within the pressurized habitat. Virtually everything else will have to be different.

ISRU methods will be different. Thermal control (for both surface habitats and spacesuits) will be different. Power production and storage will be different. Lander design will be different.

Moon: Day / Night cycle of 28 days (~200 C temperature swings from day to night), no atmosphere (thermal control must be done by radiating away the heat), much less water (excepting polar locations with permanently shadowed craters), 0.16 g gravity. ~3-4 days transit time from Earth, very frequent launch windows. <1 second radio delay for communications with Earth.

Mars: Day / Night cycle of 24 1/2 hours, less temperature extremes (~90 C from day to night), very thin atmosphere (but sufficient for some radiation protection and allows for thermal regulation by convection), much more water available in the top soil, 0.376 g gravity. ~6 months transit time from Earth with launch windows every 18 months or so. 15-40 minutes delay in radio communications with Earth.

Things like rovers and spacesuits that are designed to work on the surface of the Moon will not work on Mars, and vice versa.

If your end goal is to go to Mars, then yes, going to the Moon first is nothing but a very expensive diversion from your goal. If you want to go to Mars, then go to Mars. If you want to go to the Moon, then go to the Moon. Both are very worthy destinations for science, exploration, and future economic exploitation, but going to one does not really help you in going to the other.

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"One bit of advice: it is important to view knowledge as sort of a semantic tree -- make sure you understand the fundamental principles, ie the trunk and big branches, before you get into the leaves/details or there is nothing for them to hang on to." - Elon Musk"There are lies, damned lies, and launch schedules." - Larry J

About the only commonality would be equipment within the pressurized habitat. Virtually everything else will have to be different.

ISRU methods will be different. Thermal control (for both surface habitats and spacesuits) will be different. Power production and storage will be different. Lander design will be different.

Moon: Day / Night cycle of 28 days (~200 C temperature swings from day to night), no atmosphere (thermal control must be done by radiating away the heat), much less water (excepting polar locations with permanently shadowed craters), 0.16 g gravity. ~3-4 days transit time from Earth, very frequent launch windows. <1 second radio delay for communications with Earth.

Mars: Day / Night cycle of 24 1/2 hours, less temperature extremes (~90 C from day to night), very thin atmosphere (but sufficient for some radiation protection and allows for thermal regulation by convection), much more water available in the top soil, 0.376 g gravity. ~6 months transit time from Earth with launch windows every 18 months or so. 15-40 minutes delay in radio communications with Earth.

Things like rovers and spacesuits that are designed to work on the surface of the Moon will not work on Mars, and vice versa.

If your end goal is to go to Mars, then yes, going to the Moon first is nothing but a very expensive diversion from your goal. If you want to go to Mars, then go to Mars. If you want to go to the Moon, then go to the Moon. Both are very worthy destinations for science, exploration, and future economic exploitation, but going to one does not really help you in going to the other.

Mars has a smaller temperature range. So habitat, rover and spacesuit cooling (and heating) systems designed for the Moon will work on Mars. They will be heavy over engineered but radiating heat away still works. Same for radiation protection. A common dust protection system can probably be designed.

Having the human environment systems debugged on the Moon will save the Mars team a fortune.

Team work Moon an MarsI imagine a class with professors and students before who do both geleichzeitig. the school administration collects the knowledge and spread it back to the developer. So can all learn something. and developments are not duplicated.It's like 2 large aerospace company that can work together. and utilize the synergies. and so less tax money consuming. and move faster.

Having the human environment systems debugged on the Moon will save the Mars team a fortune.

That was the common wisdom going in to Constellation, and after a rather short while the NASA mission planners started coming back with "If you want to go to the Moon, fine, but it's an expensive side-trip if what you really want to do is go to Mars." In other words, the common-sense thought that "wringing out the bugs" on the Moon will save a fortune in going to Mars turned out -- at least while Constellation was being planned -- to be actually not true.

This isn't to say we ought not go back to the Moon. Just that going to the Moon isn't a great cost-savings testbed for Mars. By the end of Constellation, the planners were basically being told "Just go ahead and plan on the lunar option, don't worry about how it might apply to Mars." This led to the Antares lander -- which was completely optimized for lunar surface work, with practically no application to Mars planning.

Extensive high performance tele-robotic operations with gradually increasing autonomy.This is slowly being done on ISS now, lunar base would push this into much sharper focus.

Note that there are multiple terrestrial markets for this too, which keep pushing the envelope, but space robotics and mechatronics is subject to unique constraints, and even more constraints outside of the relatively radiation protected environments of LEOPlus terrestrial tele-robotics is always up against cheap human labor, so industry led applications are somewhat limited by that. In space, there won't be any cheap human labor for a long time

The thread essentially asks if what is developed for the moon could be useful for a Mars mission. But the order in the question leads to false assumptions.

There's very little that, if developed for lunar missions, would assist with Mars missions.

But oddly, discussions about using SpaceX's proposed Mars infrastructure for lunar missions shows that the opposite may not be the case.

Hardware optimised for a Mars mission might be modified for a lower cost lunar mission.

A retro-propulsion rocket-landing system build for Mars, could land a significantly larger payload on the Moon. A stage capable of getting from LEO to Mars orbit is capable of getting from LEO to lunar orbit and back. A refuelling infrastructure in LEO for reusable Mars hardware would be identically useful for reusable Lunar hardware. (Mars atmospheric ISRU probably wouldn't be transferable, but some of the actual surface refuelling infrastructure should be modifiable for a lunar-polar ISRU system.)

Likewise, an EVA suit optimised for the moon's harsh thermal regime with a soft 1/6th gravity may not be suitable for 1/3rd gravity. But a suit light enough for 1/3rd gravity might be more easily modified to carry a beefed up thermal system under 1/6th gravity.

Focus on Mars, and some of the hardware might be able to be modified for a lunar infrastructure. Focus on the moon, and very little will be useful for Mars.

[I don't mean solely MCT either. If you had a DRA 5.0 Mars system with an LEO-LMO transfer ship with separate lander(s), those landers and the engine and power module for the LEO/LMO ship would be useful for lunar missions. You just wouldn't need the long duration habitat and life-support for the Earth/Mars trip.]

{snip}Focus on Mars, and some of the hardware might be able to be modified for a lunar infrastructure. Focus on the moon, and very little will be useful for Mars.

[I don't mean solely MCT either. If you had a DRA 5.0 Mars system with an LEO-LMO transfer ship with separate lander(s), those landers and the engine and power module for the LEO/LMO ship would be useful for lunar missions. You just wouldn't need the long duration habitat and life-support for the Earth/Mars trip.]

A LEO-LLO transfer ship may not need a long duration habitat and life-support but a Moon base does.

A LEO-LLO transfer ship may not need a long duration habitat and life-support but a Moon base does.

A surface life-support is likely to be significantly different from a micro-g ECLSS. One intended for either polar or equatorial lunar day/night cycles is going to have radically different requirements to one intended for LEO, BEO-space or Mars surface.

A LEO-LLO transfer ship may not need a long duration habitat and life-support but a Moon base does.

A surface life-support is likely to be significantly different from a micro-g ECLSS. One intended for either polar or equatorial lunar day/night cycles is going to have radically different requirements to one intended for LEO, BEO-space or Mars surface.

Certain?

Cooling and energy may be outdoors but life support is indoors.

An ECLSS that works at 1-g (lab on Earth) and micro-g (spacestation & transfer vehicle) is likely to work at 1/3-g and 1/6-g

In what ways could the Moon serve as a convenient testing ground for things that might be used on Mars?

What things could be tested on the Moon before trying them out on Mars?

What are the differences between the 2 environments that would have to be accounted for?

What kind of projects might be beneficial for lunar science even while supporting greater goals for Mars?

The moon can be used to test the business case for a Mars colony.

Most of the GDP of a colony will be the generation of intellectual property. Much like Antarctica, the vast majority of people there will be researchers who's institutions or governments are paying for their time there. Residents will be a fraction of the total population.

A moon outpost let's you try out all your support functions for that economic activity, but without the time, expenses, and danger of a two year trip.

In what ways could the Moon serve as a convenient testing ground for things that might be used on Mars?

What things could be tested on the Moon before trying them out on Mars?

What are the differences between the 2 environments that would have to be accounted for?

What kind of projects might be beneficial for lunar science even while supporting greater goals for Mars?

The moon can be used to test the business case for a Mars colony.

Most of the GDP of a colony will be the generation of intellectual property. Much like Antarctica, the vast majority of people there will be researchers who's institutions or governments are paying for their time there. Residents will be a fraction of the total population.

A moon outpost let's you try out all your support functions for that economic activity, but without the time, expenses, and danger of a two year trip.

as of First maybe but i hope that Company like mars One a non governments Organisation will take or be a part of that colony

In what ways could the Moon serve as a convenient testing ground for things that might be used on Mars?

What things could be tested on the Moon before trying them out on Mars?

What are the differences between the 2 environments that would have to be accounted for?

What kind of projects might be beneficial for lunar science even while supporting greater goals for Mars?

The moon can be used to test the business case for a Mars colony.

Most of the GDP of a colony will be the generation of intellectual property. Much like Antarctica, the vast majority of people there will be researchers who's institutions or governments are paying for their time there. Residents will be a fraction of the total population.

A moon outpost let's you try out all your support functions for that economic activity, but without the time, expenses, and danger of a two year trip.

Also other business activity such as ISRU production of propellent. The equipment won't be the same as used on Mars, but the propellent can be used for flights to Mars. We'll see how the economics work out.

In short term, a interesting platform to make our first scientific colony. We could test low gravity, artificial gravity on surface, long term support, some IRSU building and manufacturing, remote telepresence, buildings for robot protection (while moon night), etc. etc.

But the key to be succesful in long term is that we need to add incremental reusable infrastructure, so we could have more and more resources while maintain a plain spending.This is the reason because I think that the Mars brute force approach I think that it has a lot of probability of a death end. Yes... you can visit Mars some times, but later would be another Apollo v2.

We need a incremental infrastructure. Only one spot, not one different each time. Robots and other machines with standard pieces to replaces ones with anothers. Custom building (3d printing or local manufacturing to make easy replacements).Ion tugs to move cargo between Earth and Moon. Tethers. Rail launcher and/or space elevator on Moon. IRSU for oxygen. Perhaps water. Local food production...

Incremental infrastructure and shared approach. A step beyond ISS. Not big rockets, but orbital depots , tethers and similar to make more missions, more shared, opened to competition and cooperation.And make the colony only get bigger. What reach Moon surface, it would be there "forever". Future recicling.

So, once the main ships (tugs, depots, tether points...) was deployed, we could lower the spending and ensure that the colony never cancels.

Because Mars mission would be bigger and less robotic, it probably be tried on a "one mission/one place" approach, and fail in long term.We need a big colony with frequent visits, new experiments, robots, IRSU...etc.Too difficult on Mars when each mission has near two years of duration.

Mars would need a very autonomous colony from start. Like a Moon base but with little mistakes.So we would need be very confident of our capabilities and resources.Probably we need to spend some decades on Moon before to try not only technologies, but organization and long term colonization.ISS approach on Moon surface with as much IRSU and reusability as possible.

Allowing the candidate to progress in their training to higher and higher levels.

Plus, it provides off-roads for the training system; because even if the person may not be cut out for Mars missions, they're still good for LEO/Lunar missions -- important if we're to move towards a space program with large masses of people living or working off-earth, instead of only a few highly trained and handpicked specialists working off-earth at any one time.

More that a stepping stone to Mars, Moon is it own destination.Very insteresting in long term, because is a very good place for robotic telepresence.

That ease of teleoperation of robotic rovers demonstrates the lack of scientific interest in the moon by major agencies.

In 40 years, NASA hasn't put a single lander or rover on the moon. They've flown a small number of low-funded orbiters, but not followed up on the interesting findings of those orbiters. Even during Constellation, which Bush justified as lowering the cost to Mars, there was no serious proposal for a lunar lander or rover, not even to do a ground assay of the supposed polar ice deposits.

And in its entire existence ESA hasn't even done a lunar orbiter.

It's one of the things I find frustrating about the talk of manned lunar missions. "You won't even fund a fracking remote-controlled rover!"

Allowing the candidate to progress in their training to higher and higher levels.

Plus, it provides off-roads for the training system; because even if the person may not be cut out for Mars missions, they're still good for LEO/Lunar missions -- important if we're to move towards a space program with large masses of people living or working off-earth, instead of only a few highly trained and handpicked specialists working off-earth at any one time.

I see your point, Ryan. I just disagree that the experience gained on lunar missions can easily be translated to missions with much farther destinations.

The best parallel to what you're describing is how NASA always says that they used the Gemini missions to train both ground support staff and flight crews for Apollo. And it's true, they used Gemini to perform maneuvers and manage missions that, in terms of complexity, did rival what they would be doing later on in Apollo.

And that's where the "preparation" aspect ended.

Apollo engineers and managers for the most part disdained lessons learned from Gemini, saying (with a faint air of superiority, as described by Mike Collins) that "it's simply not done that way in Apollo." Equipment was different, capabilities were different, operations were different.

What NASA learned from Gemini, to be honest, was the "Mission Control" paradigm for operating large, complex space flights. Mercury was so limited that the Mission Control paradigm wasn't able to expand to where it needed to be to manage an Apollo lunar expedition. It was during Gemini that everyone in the MOCR learned how to train, how to tag up with the Flight Director, how to make decisions while thirty voices were mumbling into your ear... and to select those people capable of doing it.

John Aaron didn't amass the knowledge of Apollo systems that made him a "steely-eyed missile man" working Gemini. The Gemini knowledge he gained was basically useless when he started working on Apollo systems. Just as the Apollo knowledge a lot of flight controllers had amassed was of little direct use when they started flying the Shuttle.

Now, the question really is, what can we learn that we can't learn via simulations about mounting a manned Mars mission by mounting lunar expeditions? Not how to operate the lander and surface equipment -- as has been pointed out, those hardware elements have to be a lot different for lunar landers than for Mars landers, due to quite different environmental factors.

And the real-time Mission Control paradigm has already been perfected, over a lot of years with Apollo, Shuttle and ISS. In reality, the biggest thing that has to be invented and perfected is a new Mission Control paradigm, one that can be effective when your spacecraft are not light-seconds but light-minutes away from the ground controllers.

Hence, your description of ISS = immediate help, Moon = 2-3 days from help and Mars = months from help is flawed in terms of the actual support a manned spacecraft can get from the ground. It's more like ISS = support within fractions of a second of an issue, Moon = support within three seconds of an issue, Mars = ground can't see an issue until it's likely killed you, so no effective minute-to-minute support. At all.

So, in that frame of reference, there is almost no difference between LEO and lunar operations. There is a very significant difference between both LEO and lunar operations and operations light-minutes away. Thus, you learn nothing from lunar operations in terms of supporting spacecraft that are light-minutes away. The paradigm is identical to LEO operations.

The only way to develop and perfect a new Mission Control paradigm without actually going light-minutes away from Earth is via simulation. And if you're going to simulate it, does it make sense to spend tens of billions of dollars to put humans on the lunar surface in order to put simulated 12-minute comm delays (each way) into the stream? Can't you do that with ground simulations, or even simulations of operations using assets in-place, like the ISS?

And while the development of DSH-type hab modules in cislunar space can be valuable in preparation for Mars missions, building up a cislunar infrastructure in no way requires or needs us to take jaunts from there on down the lunar surface. Any surface exploration out of a cislunar station is a separate thing from the development of habs and transit modules for Mars, and can't really help us prepare for Mars. It can only take away funding from a Mars goal.

I know that common sense says "just use the same stuff you're going to use going to Mars, just go to the Moon instead and we'll learn how to use it." Problem is, the environments, both physically and operationally, are so different that I question the value of spending tens and tens of billions of dollars on landing crews on the Moon just for the limited training and development opportunities it might provide for follow-on Mars missions. It's sort of like saying "Before we use this bathyscaphe to descend to the Challenger Deep, let's test it by descending from the rim to the floor of the Grand Canyon." Nice idea in theory, but the environmental conditions for each descent are so very different that it won't provide any useful information to apply to the mission for which you're designing the bathyscaphe.

Don't get me wrong, though. I support and encourage a return to the Moon with humans, I really do. I just think it ought to be a separate lunar exploration program, not associated with Mars expeditions. I also think that we can get international involvement in a new lunar exploration program, with ESA and JAXA providing the lunar lander and lunar surface equipment. Spread out the cost and land international crews on the Moon, using cislunar infrastructure designed to support future Mars missions.

So, if you want to get to both the Moon and Mars in the next few decades, I'd say it's possible. But it's not going to happen because the Moon is a good place to check out Mars landers and surface equipment -- because it just isn't.

But the biggest reason to go back to the Moon in my opinion is that it can act as a testing ground for TTP (tactics, techniques, and procedures) in a harsh environment with a moderate safety risk.

What advantage does operating a pretend Mars base on the moon have over operating a pretend Mars base in a remote area of Earth?

The disadvantage being the extra tens of billions of dollars necessary for NASA to operate a moon base.

I mean, if little of the hardware can be common, what benefit is there that is worth the enormous cost?

It will be a real Moon base. The Mars team just guests.

On Earth with difficulty we can simulate space by put a habitat in a vacuum chamber but we cannot drive a rover very far.

Having a genuine vacuum that undergoes very large temperature change every two weeks will force everything to be space rated and have full life support. Example problem has the MMSEV been equipped with a ECLSS yet?

building up a cislunar infrastructure in no way requires or needs us to take jaunts from there on down the lunar surface. Any surface exploration out of a cislunar station is a separate thing from the development of habs and transit modules for Mars, and can't really help us prepare for Mars. It can only take away funding from a Mars goal.

That's not necessarily true. Beefed-up versions of the Moon landers that ULA proposed based on their ACES platform could land on Mars; albeit you'd have to do it mostly fully propulsively. This was discussed here years ago. Basically you'd be trading the cost of propellant for the cost of developing a brand new Mars lander that would require a fancy EDL system where you'd use aerobraking to shed the vast majority of Mars orbit delta v.

Also, it's hard to imagine what a single stage, reusable Mars lander would be like based on the latter design because the TPS is going to weigh a lot, and the delta v for taking off is going to be basically the same as that required for a fully propulsive descent. Maybe you could have a SpaceX-style returnable 1st stage, so the actual capsule would be able to land on its own, but then it could be mated to the reusable first stage for relaunch. Sounds good, but when contemplating such monsters, the concern for lunar missions sucking away Mars funds then becomes real.

This points out two very different mind-sets when it comes to Mars exploration. There are those who prefer the Apollo-on-steroids, flags 'n' footprints, mass-starved architecture, and there are those that prefer a sustainable, long-term presence that will make evolutionary use of existing architectures, as well as space resources to ensure that something as simple as rocket propellant will always be available in an abundant supply.

As for habs, if one would suffice for the surface of the Moon, I don't see how it would not also work on Mars. If anything, it'd be a bit overengineered. But so what. The idea that brand new architectures have to be designed for Mars missions is a guarantee of massive cost overruns. According to Doug's logic, a 3rd-stage designed to boost communications satellites to GEO has no business being included in the design for a manned lunar lander. After all, satellites don't require pressurized chambers and life support systems, and the Moon's surface is a very different environment compared to LEO or GEO.

In reality, a Mars architecture based on a lunar architecture based on ULA's ACES combined with Bigelow-style habs would work admirably IMHO.

YMMV

« Last Edit: 05/21/2016 08:39 PM by Warren Platts »

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"When once you have tasted flight, you will forever walk the earth with your eyes turned skyward, for there you have been, and there you will always long to return."--Leonardo Da Vinci

building up a cislunar infrastructure in no way requires or needs us to take jaunts from there on down the lunar surface. Any surface exploration out of a cislunar station is a separate thing from the development of habs and transit modules for Mars, and can't really help us prepare for Mars. It can only take away funding from a Mars goal.

That's not necessarily true. Beefed-up versions of the Moon landers that ULA proposed based on their ACES platform could land on Mars; albeit you'd have to do it mostly fully propulsively. This was discussed here years ago. Basically you'd be trading the cost of propellant for the cost of developing a brand new Mars lander that would require a fancy EDL system where you'd use aerobraking to shed the vast majority of Mars orbit delta v.

Also, it's hard to imagine what a single stage, reusable Mars lander would be like based on the latter design because the TPS is going to weigh a lot, and the delta v for taking off is going to be basically the same as that required for a fully propulsive descent. Maybe you could have a SpaceX-style returnable 1st stage, so the actual capsule would be able to land on its own, but then it could be mated to the reusable first stage for relaunch. Sounds good, but when contemplating such monsters, the concern for lunar missions sucking away Mars funds then becomes real.

This points out two very different mind-sets when it comes to Mars exploration. There are those who prefer the Apollo-on-steroids, flags 'n' footprints, mass-starved architecture, and there are those that prefer a sustainable, long-term presence that will make evolutionary use of existing architectures, as well as space resources to ensure that something as simple as rocket propellant will always be available in an abundant supply.

As for habs, if one would suffice for the surface of the Moon, I don't see how it would not also work on Mars. If anything, it'd be a bit overengineered. But so what. The idea that brand new architectures have to be designed for Mars missions is a guarantee of massive cost overruns. According to Doug's logic, a 3rd-stage designed to boost communications satellites to GEO has no business being included in the design for a manned lunar lander. After all, satellites don't require pressurized chambers and life support systems, and the Moon's surface is a very different environment compared to LEO or GEO.

In reality, a Mars architecture based on a lunar architecture based on ULA's ACES combined with Bigelow-style habs would work admirably IMHO.

YMMV

This is actually where I am on tenterhooks awaiting SpaceX's announcement of its Mars architecture. Be it flags-and-footprints or permanent base, the NASA DRA is mass-starved. Everything we're discussing here is mass-starved.

Supposedly, SpaceX is proposing non-mass-starved architecture. If true, and if achievable, then a lot of what we're talking about here really stops being applicable...

That ease of teleoperation of robotic rovers demonstrates the lack of scientific interest in the moon by major agencies.

In 40 years, NASA hasn't put a single lander or rover on the moon. They've flown a small number of low-funded orbiters, but not followed up on the interesting findings of those orbiters. Even during Constellation, which Bush justified as lowering the cost to Mars, there was no serious proposal for a lunar lander or rover, not even to do a ground assay of the supposed polar ice deposits.

It's not about scientific achievements. It's about reducing human intervention on real cases and bring IRSU in a long term way. You can't make massive IRSU with astronauts. You need a lot of "standarized" robots, building a robot ecosystem, reusing as much parts as you could and making "robot shelters" too (not so complex like manned shelters but allowing less thermal stress on nights for example, or less dust for mainteinance).

The problem of previous architectures is that they don't take IRSU very seriously. Only for fuel, and mainly in Mars because Zubrin's Mars Direct proposal.

I say that we should make IRSU the key stone of successful space colonization. Fuel is not enough. Electronics are too complex, but bulky raw materials that surround the fragile components. Others things wouldn't use destination raw material but local production (like local printing/manufacturing) so only raw material package should be need to transport.

This approach would result in incremental results with a plain expending, that it's just what we need.A sprint Apollo project would bring a lot more results but at a price of "burn" space interest (and later budget) very quickly. We must avoid the mistakes of the past.

A International approach is needed for long term success and a incremental infrastructure too.Mars is too far, and the result would be huge effort disconnected missions. The same Apollo style of the past.

Moon could have a interconnected and redundant international cooperation and competition. With compatible but independent rockets to LEO, orbital depots or tugs in orbit, Moon landers and different Moon base modules.The small time windows allow these cooperation without too much precise timing. Only a connection of compatible infrastructure that could work for years between multiple missions.

Supposedly, SpaceX is proposing non-mass-starved architecture. If true, and if achievable, then a lot of what we're talking about here really stops being applicable...

If the plan is to get everything from the Earth, it's going to be mass starved no matter what they say.

Mars.

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Chris Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Supposedly, SpaceX is proposing non-mass-starved architecture. If true, and if achievable, then a lot of what we're talking about here really stops being applicable...

If the plan is to get everything from the Earth, it's going to be mass starved no matter what they say.

Mars.

For a Mars mission, getting resources at the Mars end is a no-brainer. Of course not lugging all of your landing, ascent, and return fuel from Earth makes sense. That said, if lunar propellants can be competitive with Earth-launched prop in either LEO or some near-lunar departure point (EM-L1, L2, or lunar NRO), then it can also play a major role. And I think with propellantless launch and eventually landing infrastructure, that the Moon can beat even RLV launch prices for propellant in LEO. And while that's controversial, I think it's less controversial to say that lunar sources can beat out earth-launched sources for propellant at the high-port at EM-L1/L2, or lunar NRO.

Now, how we get there is a different problem, but I think that if done wisely, lunar propellant could be an enabler for Mars missions. Not that you couldn't theoretically do Mars missions without lunar propellant, but that the cost equation isn't likely to come close to closing without every bit of help Mars can get (lunar ISRU, depots, martian ISRU, aerocapture, etc).

Propellantless launch isn't necessary if you have lots of reaction mass available. On Earth and Mars, that's not really a problem. This thread's author seems to claim it's not a problem on the Moon, either (though I'm skeptical).

If NASA wants to go to Mars, it'd be a huge waste for NASA to go to the Moon just for propellant. I guarantee FAR more money will be spent by stopping off at the Moon first.

Now if private companies think they can deliver lunar water or propellant to orbit for cheaper than you can get from Earth, then they should offer it to NASA for a fixed price. NASA ought to have mechanisms in place to allow that. Same for alt-launch from Earth or atmospheric scooping or asteroid resources, etc. But I guarantee NASA will explode the costs and there's simply no way it'd be cheaper for NASA to go to the Moon first.

« Last Edit: 05/24/2016 05:21 PM by Robotbeat »

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Chris Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

Propellantless launch isn't necessary if you have lots of reaction mass available. On Earth and Mars, that's not really a problem. This thread's author seems to claim it's not a problem on the Moon, either (though I'm skeptical).

Propellantless launch, when practical (it's tons more practical on the moon than either Mars or Earth) dramatically cuts down on the amount of mining and infrastructure you need in order to support a given rate of propellant export. For the Moon, there are options for propellantless launch that could be landed in a single ACES/Xeus landing that could cut the amount of prop you'd need to produce on the moon by nearly half. Half the required infrastructure, half the required landings. Could you do with out it? Sure, but you'd be stupid to.

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If NASA wants to go to Mars, it'd be a huge waste for NASA to go to the Moon just for propellant. I guarantee FAR more money will be spent by stopping off at the Moon first.

That's why I added the "if done wisely" caveat. NASA isn't going to go anywhere wisely. Congress wouldn't allow it. Which is why while I think "going to the Moon first" could be a good idea, I don't want NASA focused on doing lunar missions itself. I'd much rather them keep their sights on Mars, with the Moon being something that they support by public/private partnership. :-)

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Now if private companies think they can deliver lunar water or propellant to orbit for cheaper than you can get from Earth, then they should offer it to NASA for a fixed price. NASA ought to have mechanisms in place to allow that. Same for alt-launch from Earth or atmospheric scooping or asteroid resources, etc. But I guarantee NASA will explode the costs and there's simply no way it'd be cheaper for NASA to go to the Moon first.

Yeah, I definitely was not advocating for a return of a NASA-centric return to the Moon. I'd much rather see NASA keep wasting its big money on Mars, while participating in ESA's lunar village concept, as a contributing member, via public/private partnerships. Ie think of how ESA and JAXA support ISS today by contributing to cargo launch in exchange for a crew member, but in NASA's case, they save money by having private companies provide the cargo services, in exchange for NASA being able to send an astronaut... But keep their main focus on Mars. I don't care about Mars as much, so am less worried about NASA screwing that up. :-)

Propellantless launch isn't necessary if you have lots of reaction mass available. On Earth and Mars, that's not really a problem. This thread's author seems to claim it's not a problem on the Moon, either (though I'm skeptical).

Propellantless launch, when practical (it's tons more practical on the moon than either Mars or Earth) dramatically cuts down on the amount of mining and infrastructure you need in order to support a given rate of propellant export. ...

Not true. For Earth (water) and Mars (CO2), no mining required. An optimal Mars-to-orbit vehicle would run on CO/O2 because you don't need to do any mining. Then it's just electrolysis, which is a very small amount of infrastructure, and energy to run the propellant production. That energy is not significantly different than the energy needed to run a propellantless launch platform, and in fact, a propellantless launch platform requires a huge burst of energy which is itself a large infrastructure requirement, plus energy wasted in the launch cart (might be recovered a bit, but not at perfect efficiency and would require even more infrastructure).

...and for Earth, you don't even need electrolysis, you can use natural gas as the fuel (the cheapest, in dollar-price, form of energy available right now) and oxygen from the air.

Chris Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

I wasn't talking about propellantless launch from Mars or the Earth. You're the one who keeps bringing that strawman up.

My point was about propellantless launch of ISRU propellant from the Moon, where a) propellantless launch is *much* easier than for Earth or Mars due to the much lower orbital velocity and the lack of atmosphere you have to deal with, b) can be less infrastructure intensive than even setting up the ISRU system to feed it payloads, and c) makes a big economic difference to the cost of propellant from the lunar surface.

It'd use whatever is convenient. Could be CO/O2, but I'd guess it'd be worth it to use CH4/O2 or H2/O2 (or Argon for electric propulsion). Or send up just water and do the electrolysis in a high-orbit where you have 24-7 sunshine. The relative masses of propellant needs to be taken into account. Nothing is free, things have varying levels of difficulty to obtain so whether it's worth it to use one thing or another depends on the situation.

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Chris Whoever loves correction loves knowledge, but he who hates reproof is stupid.

To the maximum extent practicable, the Federal Government shall plan missions to accommodate the space transportation services capabilities of United States commercial providers. US law http://goo.gl/YZYNt0

My point was about propellantless launch of ISRU propellant from the Moon, where a) propellantless launch is *much* easier than for Earth or Mars due to the much lower orbital velocity and the lack of atmosphere you have to deal with, b) can be less infrastructure intensive than even setting up the ISRU system to feed it payloads, and c) makes a big economic difference to the cost of propellant from the lunar surface.

OTOH, if you have enough activity in cis-lunar space to justify the construction of any form of propellantless launch from the lunar surface, it implies you've already solved whatever problem you are trying to solve with propellantless launch.

Propellantless launch, when practical (it's tons more practical on the moon than either Mars or Earth) dramatically cuts down on the amount of mining and infrastructure you need in order to support a given rate of propellant export. For the Moon, there are options for propellantless launch that could be landed in a single ACES/Xeus landing that could cut the amount of prop you'd need to produce on the moon by nearly half. Half the required infrastructure, half the required landings.

I want to follow up on this... is there a paper somewhere I should go read? To me propellantless means magnetic catapult. Even at reeealllllly high acceleration I'd assumed you need quite a lot of mass in a launcher. When you say "could be landed" what do you mean? As a kit that someone has to put together? With some ISRU components? Or self contained? Or do you mean something that unrolls/unfurls self deploys? Does the kit include the solar cells or NTU to power it and the batteries or is that assuming an existing ISRU plant that powers this for a bit?

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"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Propellantless launch, when practical (it's tons more practical on the moon than either Mars or Earth) dramatically cuts down on the amount of mining and infrastructure you need in order to support a given rate of propellant export. For the Moon, there are options for propellantless launch that could be landed in a single ACES/Xeus landing that could cut the amount of prop you'd need to produce on the moon by nearly half. Half the required infrastructure, half the required landings.

I want to follow up on this... is there a paper somewhere I should go read? To me propellantless means magnetic catapult. Even at reeealllllly high acceleration I'd assumed you need quite a lot of mass in a launcher. When you say "could be landed" what do you mean? As a kit that someone has to put together? With some ISRU components? Or self contained? Or do you mean something that unrolls/unfurls self deploys? Does the kit include the solar cells or NTU to power it and the batteries or is that assuming an existing ISRU plant that powers this for a bit?

"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

My point was about propellantless launch of ISRU propellant from the Moon, where a) propellantless launch is *much* easier than for Earth or Mars due to the much lower orbital velocity and the lack of atmosphere you have to deal with, b) can be less infrastructure intensive than even setting up the ISRU system to feed it payloads, and c) makes a big economic difference to the cost of propellant from the lunar surface.

OTOH, if you have enough activity in cis-lunar space to justify the construction of any form of propellantless launch from the lunar surface, it implies you've already solved whatever problem you are trying to solve with propellantless launch.

I disagree. As I mentioned to Chris, I see some propellantless launch options that could be put in place with a single ACES/Xeus lander. And halving the amount of lunar LOX/LH2 you need to deliver a kg of LOX/LH2 to LEO makes a huge difference.

I want to follow up on this... is there a paper somewhere I should go read? To me propellantless means magnetic catapult. Even at reeealllllly high acceleration I'd assumed you need quite a lot of mass in a launcher. When you say "could be landed" what do you mean? As a kit that someone has to put together? With some ISRU components? Or self contained? Or do you mean something that unrolls/unfurls self deploys? Does the kit include the solar cells or NTU to power it and the batteries or is that assuming an existing ISRU plant that powers this for a bit?

I've been meaning to do a blog post on this, but it's been a previous topic on this forum (hint, hint). But yeah, I think a single ACES/Xeus lander could land the main system and the rest of the "kit" to setup a specific type of propellantless launch system that could put 1mT payloads into lunar orbit on a regular basis.

"I think it would be great to be born on Earth and to die on Mars. Just hopefully not at the point of impact." -Elon Musk"We're a little bit like the dog who caught the bus" - Musk after CRS-8 S1 successfully landed on ASDS OCISLY

Solar Tubes filled with sand or dust to collect sunlight are a simple ISRU technology. On the Moon we may not even need the glass, just a metal or plastic tube.

Video

The heat can be used directly to warm water. There should be sufficient heat to create electricity using a low temperature difference Sterling engine. Nitrogen, argon or carbon dioxide can be used as the working gas.

This technology is essentially a land based train that takes excess electrical energy and stores it through potential energy gained in large train masses. In rudimentary terms, itís the equivalent of pushing a large rock up a hill when you have the energy so you can push it down later when you need more energy.

This technology is essentially a land based train that takes excess electrical energy and stores it through potential energy gained in large train masses. In rudimentary terms, itís the equivalent of pushing a large rock up a hill when you have the energy so you can push it down later when you need more energy.

Those are designed for a short spurt of energy to stabilise the grid (a tricky thing). Not all-night power.

Yeahhhhh... wildly inefficient from a volume: power perspective and on the Moon, six times less efficient than *that.*

« Last Edit: 08/16/2017 11:17 AM by Lampyridae »

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SKYLON... The League of Extraordinary Gentlemen's preferred surface-to-orbit conveyance.

I want to follow up on this... is there a paper somewhere I should go read? To me propellantless means magnetic catapult. Even at reeealllllly high acceleration I'd assumed you need quite a lot of mass in a launcher. When you say "could be landed" what do you mean? As a kit that someone has to put together? With some ISRU components? Or self contained? Or do you mean something that unrolls/unfurls self deploys? Does the kit include the solar cells or NTU to power it and the batteries or is that assuming an existing ISRU plant that powers this for a bit?

I've been meaning to do a blog post on this, but it's been a previous topic on this forum (hint, hint). But yeah, I think a single ACES/Xeus lander could land the main system and the rest of the "kit" to setup a specific type of propellantless launch system that could put 1mT payloads into lunar orbit on a regular basis.

~Jon

Like a whopping big trebuchet, sling etc?

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SKYLON... The League of Extraordinary Gentlemen's preferred surface-to-orbit conveyance.

Yeahhhhh... wildly inefficient from a volume: power perspective and on the Moon, six times less efficient than *that.*

Unless .. you are using local materials.

Train tracks are heavy. You *could* use a simple winch and pulley system. But then you have a lot of bracing etc etc etc. And it's still six times less energy storage than on Earth. Gravity storage is woefully weak.

Then there's lunar dust getting in the gears.

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SKYLON... The League of Extraordinary Gentlemen's preferred surface-to-orbit conveyance.

When comes to surviving 14 day lunar night here 3 options 1) Nuclear.2) Space Based Solar power beamed to surface.3) LH/LOX. Can generate 2kW/hr per kg, but takes lot more than that to convert it back from water to LH/LOX.

this would be to prove that the notion of glass domes would or would not have been a viable on the moon.

Domes are compression structures, they are rarely viable when containing a higher pressure (such as air, in a vacuum.) If you are containing pressure, it is, by definition, a pressure vessel and hence should be shaped like a pressure vessel.

(Even if you pile mass on top of the dome to artificially outweigh the force from the contained gas, that gas is still trying to blow out the sides, particularly where the floor joins the side (and that's assuming a gas-tight floor.) Hence the optimal shape would still be a classic pressure-vessel, but "squashed" by the top mass. A low, oblate spheroid, or elongated, ellipsoidal equivalent.)

[Nothing to do with energy storage, just one of those SF tropes that annoys me.]

this would be to prove that the notion of glass domes would or would not have been a viable on the moon.

Domes are compression structures, they are rarely viable when containing a higher pressure (such as air, in a vacuum.) If you are containing pressure, it is, by definition, a pressure vessel and hence should be shaped like a pressure vessel.

(Even if you pile mass on top of the dome to artificially outweigh the force from the contained gas, that gas is still trying to blow out the sides, particularly where the floor joins the side (and that's assuming a gas-tight floor.) Hence the optimal shape would still be a classic pressure-vessel, but "squashed" by the top mass. A low, oblate spheroid, or elongated, ellipsoidal equivalent.)

[Nothing to do with energy storage, just one of those SF tropes that annoys me.]

Or my favourite: the spiralled glass turd.

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SKYLON... The League of Extraordinary Gentlemen's preferred surface-to-orbit conveyance.

When comes to surviving 14 day lunar night here 3 options 1) Nuclear.2) Space Based Solar power beamed to surface.3) LH/LOX. Can generate 2kW/hr per kg, but takes lot more than that to convert it back from water to LH/LOX.

2a) Earth based power beamed to the surface (if you are on the lunar nearside and have multiple earth beaming stations)

When comes to surviving 14 day lunar night here 3 options 1) Nuclear.2) Space Based Solar power beamed to surface.3) LH/LOX. Can generate 2kW/hr per kg, but takes lot more than that to convert it back from water to LH/LOX.

2a) Earth based power beamed to the surface (if you are on the lunar nearside and have multiple earth beaming stations)

That would be as expensive to develope as the moon colony itself. And highly inefficient as well.

When comes to surviving 14 day lunar night here 3 options 1) Nuclear.2) Space Based Solar power beamed to surface.3) LH/LOX. Can generate 2kW/hr per kg, but takes lot more than that to convert it back from water to LH/LOX.

4) Normal solar. Site the base at one of the poles, near a peak of (nearly) eternal light. That limits your dark time to a few days, depending on how high you can mount the panels.

When comes to surviving 14 day lunar night here 3 options 1) Nuclear.2) Space Based Solar power beamed to surface.3) LH/LOX. Can generate 2kW/hr per kg, but takes lot more than that to convert it back from water to LH/LOX.

4) Normal solar. Site the base at one of the poles, near a peak of (nearly) eternal light. That limits your dark time to a few days, depending on how high you can mount the panels.

Regenerative fuel cells seem to be what NASA is leaning towards. The peaks of "eternal light" are nice but limit the base locations severely.

Which ever system you use there is significant extra mass and complex equipment. With SBSP most of mass and complex equipment is in orbit where delivery costs from earth are lot cheaper. Surface assets are fixed solar panels. The other plus is satellite can supply multiple bases as it orbits. If only one satellite is used, base will still need storage for when satellite is over horizon. Add extra satellite and you double power production for multiple locations. Laser transmission is not very efficient compared to microwave but surface receiving equipment for laser is solar panel compared to complex rectenna and power conversion equipment.

Besides landing costs of lunar power systems there is also the assembly and on going maintenance.

The peaks of "eternal light" are nice but limit the base locations severely.

It limits you to the only parts of the moon that justify a manned presence. It prevents you from putting ISRU-fuel in the "too hard" basket and instead adopting what turns out to be a higher-risk, Altair-like strategy; which, due to added size and cost of the lander, and hence size and cost of the launcher, results in more and more of the actual "base" being deferred forever and the goal being reduced to flags'n'footprints redux. It therefore ensures that the only Mars-related thing which can be tested on the moon (ISRU-fuel related activities) is actually tested on the moon.

Kitchen equipment for the galleys. If we cannot design machines for both which work in a shirt sleeves environment we are not trying. Kettles, food mixers, fridges, microwave ovens, blenders and conversional ovens are likely to be needed. With reduced gravity motorised equipment may need fastening to the work surface. Water handling equipment on Earth, including sinks, assumes 1g to provide pressure.

Kitchen equipment for the galleys. If we cannot design machines for both which work in a shirt sleeves environment we are not trying. Kettles, food mixers, fridges, microwave ovens, blenders and conversional ovens are likely to be needed. With reduced gravity motorised equipment may need fastening to the work surface. Water handling equipment on Earth, including sinks, assumes 1g to provide pressure.

Kitchen equipment for the galleys. If we cannot design machines for both which work in a shirt sleeves environment we are not trying. Kettles, food mixers, fridges, microwave ovens, blenders and conversional ovens are likely to be needed. With reduced gravity motorised equipment may need fastening to the work surface. Water handling equipment on Earth, including sinks, assumes 1g to provide pressure.

You're assuming that 0.165g is a suitable test for 0.38g.

{snip}

I am assuming that if it works at 1g and 0.165g then the device is highly likely to work at a middle value like 0.38g.

I am assuming that if it works at 1g and 0.165g then the device is highly likely to work at a middle value like 0.38g.

If you're just checking whether a relatively off-the-shelf Earth system still works at reduced gravity -- eg, whether water still flows through a tank/pipe/tap/drain/pump/recyc -- you don't need a lunar base, it's a relatively simple yes/no question. A small unmanned elongated satellite in LEO, spun for low gravity, would give you that information for a tiny, tiny, tiny, tiny fraction of the cost of building and maintaining a manned lunar base.

Surely the point of the question is whether things designed for the unique conditions of the Mars (things not suitable for testing on Earth) can be tested on the moon, or things built especially for the moon can be generalised for Mars. And, implied, whether that's enough justification for using the moon as a stepping stone to Mars. Does it make things easier/cheaper?

[It'd be different if a lunar base cost about the same to run as, say, a remote research station on Earth. But you still wouldn't be justifying a lunar base as a Mars experiment, it'd simply be a lunar base for its own sake. You'd send stuff to be tested simply because it's there. Just as you would use an existing spin-station in LEO for testing rather than build a bespoke test satellite (or the moon), simply because it's already there and paid for.]

I am assuming that if it works at 1g and 0.165g then the device is highly likely to work at a middle value like 0.38g.

If you're just checking whether a relatively off-the-shelf Earth system still works at reduced gravity -- eg, whether water still flows through a tank/pipe/tap/drain/pump/recyc -- you don't need a lunar base, it's a relatively simple yes/no question. A small unmanned elongated satellite in LEO, spun for low gravity, would give you that information for a tiny, tiny, tiny, tiny fraction of the cost of building and maintaining a manned lunar base.

Surely the point of the question is whether things designed for the unique conditions of the Mars (things not suitable for testing on Earth) can be tested on the moon, or things built especially for the moon can be generalised for Mars. And, implied, whether that's enough justification for using the moon as a stepping stone to Mars. Does it make things easier/cheaper?

[It'd be different if a lunar base cost about the same to run as, say, a remote research station on Earth. But you still wouldn't be justifying a lunar base as a Mars experiment, it'd simply be a lunar base for its own sake. You'd send stuff to be tested simply because it's there. Just as you would use an existing spin-station in LEO for testing rather than build a bespoke test satellite (or the moon), simply because it's already there and paid for.]

You are assuming that the only reason for a Moon base is as a test facility for Mars. There are plenty of other reasons for building a Moon base. A lunar establishment is likely to have its own galley, bathroom, bedrooms, life support, land transport, communications and work areas. Designing a second version of that equipment will increase the cost and time scales of the Mars manned mission.

You are assuming that the only reason for a Moon base is as a test facility for Mars.

No, I'm assuming that was the premise for the thread. Given that it spun off from the moon-first-then-Mars vs Mars-only argument.

Do not forget the third option Moon only.

Again, I'm talking about the topic for the thread. Not a general discussion on "What do I think NASA/humanity should do in space next?", but a subset of the discussion, "What is the value of the moon to Mars exploration?" focusing down to testing/trials.

[Don't get me wrong, I'm more than happy to have that broader discussion/debate/argument/angry-rant/insults/Mod-warnings/thread-locked-with-several-users-banned, but this is not that thread.]

I am assuming that if it works at 1g and 0.165g then the device is highly likely to work at a middle value like 0.38g.

If you're just checking whether a relatively off-the-shelf Earth system still works at reduced gravity -- eg, whether water still flows through a tank/pipe/tap/drain/pump/recyc -- you don't need a lunar base, it's a relatively simple yes/no question. A small unmanned elongated satellite in LEO, spun for low gravity, would give you that information for a tiny, tiny, tiny, tiny fraction of the cost of building and maintaining a manned lunar base.

Surely the point of the question is whether things designed for the unique conditions of the Mars (things not suitable for testing on Earth) can be tested on the moon, or things built especially for the moon can be generalised for Mars. And, implied, whether that's enough justification for using the moon as a stepping stone to Mars. Does it make things easier/cheaper?

[It'd be different if a lunar base cost about the same to run as, say, a remote research station on Earth. But you still wouldn't be justifying a lunar base as a Mars experiment, it'd simply be a lunar base for its own sake. You'd send stuff to be tested simply because it's there. Just as you would use an existing spin-station in LEO for testing rather than build a bespoke test satellite (or the moon), simply because it's already there and paid for.]

NASA does not have to justify building a lunar base as a Mars experiment but using part of an existing lunar base to test Mars equipment.

Any engineer designing equipment for Mars has to say why for say an additional 20% in cost the equipment cannot be used on both the Moon and Mars. ISRU equipment that processes Mars's atmosphere cannot be used on the Moon because the Moon does not have an atmosphere. Where as knives and forks will work on both planets.

I read the DRM 5.0 at the pool over the summer, and here's my 2 cents:

There are many more things that can go wrong, and things are much harder to fix away from this planet. Testing things out on the moon would allow us to detect many more unknown failure modes and unworkable solutions than any testing on earth would do, even if there are still quite a lot of things that can only go wrong on a single location. On the moon, the risk of loss of mission can be relatively low if rockets are kept ready to send whatever is needed to fix the problem (relatively because some unknown failures will not have solutions ready for launch), while loss of crew is highly unlikely. On Mars, any dumb mistake (in hindsight) can result in loss of mission, at best. Considering the thousands and thousands of things that might potentially go wrong, going to Mars with only Earth training will result in a few loss-of-mission scenario's, like the searches for polar passages (but hopefully without loss of crew). After a few failed missions, a test phase on the moon would look far more reasonable in hindsight.

Of course, doing these tests on the moon should be done in a moon-oriented mission, not only as a precursor to Mars.